Part I - NCC · NCC-2011 Tutorial. 2. Jayashree Ratnam Fiber-to-the-Premises ... Mid band...

Part I • Fiber-to-the-Premises Technology

• Next Generation Passive Optical Networks

Part II• PHY/MAC Layer Issues

• Studies on WDM-Based Passive Optical Networks

Jayashree

Ratnam

Fiber-to-the-Premises

NCC-2011 Tutorial 2

Jayashree

Ratnam


NCC-2011 Tutorial 3

• Introduction

• Evolution of fiber-based broadband access

• PON Architectures and Enabling Technologies

• ITU-T/IEEE Standard Configurations

• Deployment Scenario and State-of-the art

• Field Trials and Test Bed Studies

• Summary

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Access Network is the last (or first) mile of the telecom infrastructure between the central office and the user

Dial-up through PSTN using DSL and Cable-modem technologies were primary methods for broadband access

Desire to access the Internet with a high-speed connectionand multimedia services requires >1Mbps/user (broadband)

Paradigm shift from Telco-centric (circuit-switched) to IP-

centric (packet-switched) transport

Lack of optical RAM rules out simple extensions to electronic counterparts

Support for heterogeneous traffic: -

bursty/constant bit rate/real time/non real-time-

digital video, telecommuting, multimedia interactive services -

efficient and high speed IP service: multicast /broadcast-

narrow and broadband analog services

Need for capability to internetwork

with network core to support end-to-end connectivity

Introduction

Technology Speed Typical Range

ADSL 2 Mbps 5.5 Km

VDSL 20 Mbps 1.0 Km

Coax 2 Mbps 0.5 Km

WiFi 54 Mbps 0.1Km

WiMax 28 Mbps 15 Km

3G Cellular 10/6 Mbps few Km

3G LTE 100 Mbps 10-15 Km

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Existing Access Technologies

WAN MAN AccessNetwork

Telecom Connectivity

MAN AccessNetwork

client

server

Presenter

Presentation Notes

6

Classification of Access Networks

Service Bandwidth –

Narrow band (33.6 Kbps voice modem)-

Mid band (ADSL-9/0.8 Mbps ; VDSL-50/2 to 25 Mbps) -

Wide band (FTTH & PON)Symmetry –

Symmetric (Telephony)-

Asymmetric (Internet, Video)Broadcast/Switched –

Broadcast (cheaper, NIU identical, Intelligence in NIU)-

Switched (Security, fault location, Intelligence in n/w)Shared/Dedicated –

Shared (Bursty

traffic, NIU operates at aggregate rate) -

Dedicated (CBR Traffic, QoS, NIU operates on fixed BW)Network Services -

Telephone, Broadcasting or Cable TV, xDSLWiMax

for BWA, Cellular telephonyFTTH, LAN / WLAN

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Fiber based Access Networks

• HFC (Hybrid fiber coax)

-

Up gradation of analog coaxial services-

Unidirectional and simple management-

Star coupler based tree topology-

NIU separates telephone and video signals-

Supports digital information transferVideo -

5 to 550 MHz, AM-VSB, 6MHz TV signalsData -

30 Mbps (downlink) & 5-40 MHz band (uplink)-

Limited upstream BW and powered amp. sections

TapAmp

HE RN

Coax

HE –

Head End

RN –

Remote Node

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Fiber based Access Networks

CO ONU NIUFiber Coax

CO -

Central office

ONU –

Optical Network Unit

NIU –

Network Interface Unit

Feeder Network Distribution Network

Depending on the fiber proximity -

FTTH, FTTC architectures evolved

• FTTC (Fiber to the Curb) -

Data digitally transmitted-

CO to ONUs

-

feeder ; ONU to NIUs

-

distribution -

ONUs

share BW using TDM or ATM techniques-

ONU serves 8-64 homes (NIUs)-

Needs an overlay HFC network for analog video-

Attractive to new entrants

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Common Topologies

HUB/CO

Remote Node

Remote Node

NIU

NIU

• Star -

Local /Rural telephone network-

Simple subscriber equipment-

Scalability straight forward

• Tree -

Multiple bus network-

TDM equipment necessary-

Good scalability

• Ring –

Minimal amount of cable -

TDM for broadband transport -

Limited scalability

CO

RN RN

RN

NIU

NIU

NIU

Access NetworkBackbone Network

FeederCollection &

Distribution NIU: Network Interface Unit

RN: Remote Node

CO: Central Office

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CO -

Central office

ONU –

Optical Network Unit

NIU –

Network Interface Unit

OLT –

Optical Line Terminal

RN–Remote Node

CO ONU NIU

Fiber Fiber/Coax/Wireless

Feeder Network Distribution Network

• Fiber needs to be deployed close To The user Premises for broadband services ---FTTP

• Fiber Access supports triple play services (voice, video and data) and is scalable with tree topology

• FTTP is a cost sensitive segment and mandates network resources to be shared

• Passive , point-to-multipoint architectures called passive optical networks (PONs) are widely accepted

• Service providers are adopting content-based revenue as the business model as against BW-based model

• Easy to install, provision, maintain and troubleshoot

• Reliable, high BW platform and smoothly integrates into any CO equipment or out-side plant

OLT RN

ONUs

ONU

ONU

ONU

Fiber-based Access Network

Passive Optical Network (tree-based)

Fiber to the Premises

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Presenter

Presentation Notes

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Variants of PONs

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Time Division Multiplexing PONs

(TDMPON):• TDMPON uses Passive splitter devices for channel distribution and aggregation through the remote nodes

• IEEE/ITU-T standardized PONs

(G. 983/4 series) are single carrier-based and employ ATM/TDM

- ATM, BPON-

Ethernet PON, GEPON- GPON

Wavelength Division Multiplexing PON (WDMPON):•WDMPON ensures high bandwidth, dynamic service provisioning and transparency

•WDMPON uses Routing devices for channel distribution and aggregation

Laser

Receiver

Splitter/C

ombiner

Receiver

Laser

Receiver

Laser

. .

CO/OLTRN

ONUBroadcast Select TPON

Wavelength Routed PON

Receiver

Laser

Receiver

Laser

. .

WDM Laser

Receiver

CO/OLTRN

ONU

0

1

N

ONU

AWG

Combiner

0

ONU

1

0

Presenter

Presentation Notes

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A Typical FTTP Deployment

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Presenter

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PON Application -

Feeder Configurations

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PON Applications-

Feeder Configurations

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Desirable Features for the PONs

•High BW, QoS

and smooth connectivity within/amongst user-clusters-Dynamic bandwidth allocation, separate MAC protocols-

service differentiation in WDMOAN

• Cost-effective deployment-

Passive architectures with shared fiber segments

• Scalability and Resource Provisioning-

Hybrid access/multiplexing technology (WDM/TDM/SCM/OCDM)

• Security, fault tolerance and support for bursty

traffic-

Encoded access schemes like OCDMA; unpowered

PON less prone to failures-

maximize resource utilization with scalability in W-OCDMA PON

• Service transparency, link upgradeability and network reconfiguration- WDM and wavelength routing in the optical layer (WR-WDMPONs) -

assessment of signal quality in WDMPON

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Deployment Scenario

Global:• Approximately 76% of the world's FTTH subscribers reside in the Asia/Pacific region. By 2006, Japan had FTTx

connectivity to 67 million domestic subscribers

• The Asia/Pacific region, Latin America and the Middle East/Africa regions will see very high growth rates

• By year-end 2010, the US will have had over 179 million broadband subscribers.

•Total worldwide DSL subscribers will have reached 371 million at

year-end 2010

•Mobile wireless broadband subscribers continue to grow rapidly as service providers roll out 3G and 4G services

• North America continues to be the largest market for cable modem services.

India:•India announced a National Broadband Plan of connecting close to

160 million households (existing10.3 M connections)

•As part of the NBP, TRAI hopes to have 60 M wireless broadband, 22 M DSL and 78 M Cable Internet users, by 2014

•State Optical Fiber Agencies (SOFA) in each state under a National Optical Fiber Agency (NOFA) Speeds of upto

10 Mbps downlink are expected in cities.

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Standards Forums

The Broadband Forum: • Central organization driving broadband wire line solutions• Empowers converged packet networks for vendors, service providers and customers •

Develop multi-service packet network specifications: interoperability, architecture and management.

Full Service Access Network: • Task group studies evolution of optical access systems beyond GPON. • NGA task group studies technology and architecture options for

NGOANs

(e.g. 10 Gbit/s, reach/split)

FTTH Council: • Consists of providers of FTTH services and companies involved in planning/building FTTH networks.• The Council members share knowledge and build industry consensus on key issues surrounding fiber to the home. • Educate the public about FTTH solutions and to promote the deployment of fiber to the home

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Study Groups

• IEEE 802.3 Ethernet Working Group:-

IEEE Std 802.3z-1998, Gigabit Ethernet

-

IEEE Std 802.3ae-2002, 10Gb/s Ethernet-

IEEE Std 802.3ah-2004, Ethernet in the First Mile -

IEEE Std 802.3av-2009, 10Gb/s PHY for EPON

• ITU-T Study Group 15 (2009-12):-

Optical transport networks and access network infrastructures -

Study Group 15 works on DSL and optical access and backbone technologies. -

SG15 standards (ITU-T Recommendations) relating to passive optical networks (PONs).

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APON (ATM Passive Optical Network)/BPON

-

A G.983 Standard adopted by ITU-T in 1999

-

155Mbps/622 Mbps downstream; 20 Km

-

Bursts of ATM cells at 155 Mbps upstream

-

OAM features (auto ranging, BER monitoring, security, auto-discovery)

- Named BPON after adding broadcast video overlay on 1550 nm

- BPON defined in ITU Rec. G.983.1/2/3

Standard Configurations-APON/BPON

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Standard Configurations-EPON

EPON (Ethernet PON)

-

An effort to accommodate IP dominant traffic in the year 2001

- Extension to IEEE 802.3 MAC (sub layer with a family of PHY layers)

- Point to multipoint topology with passive splitters

- Work within IEEE Ethernet in the First Mile group and standardized in Sept. 2004

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Standard Configurations-GPON

GPON (Gigabit Passive Optical Network)

-

Efforts of FSAN and ITU-T in 2001

-

Full service support (Voice, Ethernet, ATM, Leased lines)

-

Symmetric 622 Mbps or Asymmetric 2.5/1.25 Gbps

; 20-60 Km

-

Transport frames encapsulated to enable fragmentation

-

QoS

implemented taking SLAs

into consideration

-

ITU adopts GPON spec.s

as Rec. G.984x

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WDMPON ConfigurationsONU1OLT 1.5 m

ONUN

1.5 m

1.5 m DFB Laser

1 x N splitter

Power splitter-based WDMPON architecture

1.5 m

1.3 m

Burst- mode Receive r

1. 3

m

1. 3

m

Receive r

FP Laser

Receive r

FP Laser

...

Receiver array

ONU1

Passive branching device

ONUN

N+N

N

1+N

Multi- wavele ngthsou

rce

1 x N Route

r

Receive r

Source

Receive r

Source

Routed-based WDMPON architecture

1 , 2 …..N

1

1+N , 2+N …..N+N

OLT

WDMreceiver

...

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•

WDM-based PON ensures very high bandwidth, flexible service provisioning and transparency

• ONUs

operate at individual data rates; OLT –Array/tunable lasers

• Architectural Choice:Broadcast star

-

good connectivity, inherent multicast feature

-

splitting losses, security riskWavelength routing

-

reliable, dedicated high capacity paths- no

sharing , no splitting losses, limited connectivity

•

23

• NGI-ONRAMP (MIT, Nortel Networks, AT&T, JDS Uniphase

..)

-

Focuses on feeder network and uses power-splitting and TDMA in distribution

• SONATA (European Union)-

Centrally scheduled all traffic (WDM/TDM) and is not easily scalable

• SUCCESS (Stanford University)-

Half duplex mode communication limits the channel rate

• CPON, PSPON (British Telecom Labs)-

Splitting loss in the downstream and burst mode transceivers in

the upstream

•LARNET, RITENET (AT& T Labs)-

Double-fiber connectivity and spectrum slicing loss in LARNET and round

trip losses in RITENET

• AWG-Based WDMPONs

(S. Korea, Japan) -

Suitable choice and merits from low loss and configurability

Some Test-bed Studies

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• Larger areas and higher subscriber density • Collection & distribution network : Passive

star/ tree/ bus • Feeder network : Configurable WDM ring/

mesh ;wavelength-routed• Access node : Electronic/Optical switching

Electronic switch - IP, ATM, SONET, FRProtection, QoS

Optical switch - Reconfigurability;Differentiated QoS, Traffic grooming, Optical Protection and restoration, n/w management & control

• Traffic: Intra cluster from C/D n/wInter cluster from Feeder n/w

NGI-ONRAMP (Next Generation Internet -Optical Network forRegional Access using Multi-wavelength Protocols)

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RSPS 2010 -

Tutorial

Field Trials and Test-Bed Studies

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ACTS-PELICAN SUPERPON

• An access network, based on the ATM-based SuperPON

approach, connected via an ATM switch to a metropolitan/regional transport ring network and a meshed core network

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SUCCESS –TDM-WDMPON

PIEMAN

27


•

WP 2 -

10 Gbit/s

PON optoelectronics: focuses on upstream burst mode operation at 10 Gbit/s

with amplified reach of 100km.

•

WP2-Tunable ONU: investigates a wavelength tunable 10 Gbit/s

transmitter capable of achieving access cost targets when manufactured in volume.

•WP3 -Reflective ONU: design, develop and characterize a reflective ONU

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Gigawam

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TDM-Based PONs

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Current Deployment Statistics

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Current/ Near Future Deployment Scenario

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PON Projected Deployment

•

Massive Chinese PON equipment orders drive 16% market gain in 2Q09

• Asia Pacific PON port shipments tripling 2008 to 2013

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•Access Solutions with Evolutionary Approach (XGPONs)

• Access Solutions with New Approach (WDMPONs)

• Futuristic Convergent Access Solution (FiWi

Access)

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NGPONs

-

Need

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• FTTH-

low cost, low energy technology (50% reduction in lifetime emissions)

•NG-PONs

are expected to deliver: new and legacy services, both analog (e.g, QAM-subcarrier

multiplexed video) and digital, in a single converged conduit

•Including new services -

mobile backhaul networks with high accuracy of the clock timing for mobile services

•Optimized technology combinations in terms of cost, performance and energy saving

•Longer reach and higher splitter ratios-PHY issues in NG-PONs

–

role of optical amp.s

•Traffic pattern has been asymmetric and hubbed-this may be changing

36

Driving Factors

• Advances in photonic technologies

• Worldwide deployment of optical fiber

• Consolidation of xPON

technologies

•

Expected popularity of HDTV, video-on-demand, interactive-learning etc.

• Estimated demand: 30 Mb/s guaranteed BW per user

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Driving Factors

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Access Scenario in Near Future

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Roadmap for NGPONs

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[EMPP09]

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General Requirements for NGPONs

• Services

-

Support business/residential and mobile backhaul

-

support legacy POTS/T1/E1 as well as Ethernet

• Architecture

-

FTTx

(x:cell/office etc.)

-Splitter location

-

Resilience (protect high value services)

• Physical Layer

-

Data rate (2.5 -

10.0 Gbps)

-

Power budget (28.5-31 dB)

-

split ratio (1:64/32 and economics-based)

-

Reach (20/extended 60)

• System

-

Power saving (OPEX reduc. and green tech.)

-

QoS

and Traffic Mgmnt. (BW for RT and priority class for NRT)

-

Synch. with mobilebackhaul

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NGPON Architectures -

Evolutionary

I. Asymmetric XGPON

• Avoids burst mode transceivers

• Multiple ch.s

for ONUs

with TDMA

-spectrum compatibility and complexity of TDMA hardware

• Asymmetry typically 4:1 or 2:1 (GPON like)

• Dispersion in downstream channels

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[EMPP09]

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Evolutionary

II. Symmetric XGPON

• More challenging PHY

•Analogous to WDM txmn. Links

• Link budget 8dB worse than 2.5 Gbps

ch.s

• Needs FEC, APDand

OAs

• Uses G.652fiber at 1310 nm with DCF

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[EMPP09]

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Evolutionary

III. Hybrid DWDM/XGPON

• DWDM technology, colorless ONUs

& WDM filter

• Split ratio upto

1000 and aims for CAPEX/OPEX savings

• Used when feeder fiber is at premium

• 10Gbps DS and 2.5 Gbps

US

• Seed-light injected RSOA and tunable LD

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Evolutionary

• WDM in both directions

• GPON ONUs

must have a λ-filter to block NGPON λs

•

Addl. Preplacement

WDM filter protects GPON OLT from service outage and NGPON signals

• WDM in DS and TDMA in US

•Employed when earlier system uses widest spectrum upstream (eg., 1260-1360nm)

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NGPON Architectures (Revolutionary) -WDMPONs

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NexGen

Hybrid Access Solution (FiWi

)

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PHY/MAC Issues in PHY/MAC Issues in NGPONsNGPONs

Studies on WDMStudies on WDM--Based Access NetworksBased Access Networks

48

• PHY/MAC Issues in Next Generation PONs

•

MAC Protocols for Real-time/Non-real-time traffic in a WDMOAN

• Transmission Impairments in a WDMPON

• Resource Provisioning in a Hybrid WDM-OCDMA PON

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PHY Layer Issues -

TDMPONs

Transceivers: • OLT

–

Continuous mode transmitters for broadcast-downstream traffic

-

Burst mode receivers to handle varying power levels

• ONU –

Burst mode transmitters (limited activity in upstream traffic)during pre-assigned time slots

-

Continuous mode receivers for downstream traffic

• Burst mode laser drivers: -

Fast on/off speed (6-13bits at 1.25 Gbps)-

power suppression during idle period (<-45dBm in EPON)-

Stable emission during on-period (feedback control by PD)

• Burst mode receivers: -High sensitivity, Wide dynamic range & Fast response time

-Dynamic sensitivity recovery-

Level recovery thro’

feedback/forward structures-

Clock recovery thro PLL (ONUs

lock to OLT clock)

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• Transceivers

PHY Layer Issues -

WDMPONs

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• Wavelength plan

• Mandatory FEC for high loss budget RSC (255,223)-13% overhead; 64B66B line encoding of FEC

• Multi-rate burst mode reception

• A spectrally flat preamble pattern

• Word-aligned framing concept-

5 byte GEM header and 13 byte PLOAM message do not align with typical data transfers

• Expansion of the G-PON encapsulation method -GEM-

protocol support -features, such as an expanded ONU and T-CONT address space,

-

improved signaling methods-

more precise bandwidth reporting

PHY/MAC Issues -

GPON

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Long-reach NGPONs:• Network protection• Signal integrity with OA (especially SOA) against power variations at 10’s of microsec• Multiplexing several PONs

at the reach extenders

Backhaul for Mobile:•NG-PON shall provide an accurate transfer capability to the phase and time information from OLT to ONUs• Takes all propagation delay and processing delay into account

PHY /MAC Issues in NGPONs

53

• To drive the PON cost down, an efficient, and scalable solutions are important-

Dynamic bandwidth allocation based on an interleaved polling scheme with an adaptive cycle time

-

In-band signaling that allows a single wavelength for both downstream data and grants transmission

• Access Mechanism-

Data and Control Channels-

Sharing Mechanisms-

Ranging to Counter distance variation-

Collision Control (preamble and guard time)

• Security (denial of service, eavesdropping, masquerading):-

Encryption and Authentication specified in GPON Std. ITU G.984

• Scheduling -

Dynamic Bandwidth Assignment-

Priority Queuing for Differentiated services-

Service Level Agreements

MAC Layer Issues –

EPON/GPON

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Include interrelated issues like: • Access Protocols with/without QoS

awareness -

OLT

polls ONUs

and issues grants based on predetermined policies-

CSMA/CA with back-off medium access control

•Scheduling Algorithms -guarantee bandwidth efficiency and fairness between up/down transmissions- keep track of the status of all shared resources

I. Sequential scheduling algo. using FIFO queueing-simple to implement ;lacks efficiency and fairness guarantee

II. Batching earliest departure first

algorithm -allows prioritized transmissions;complex

optimization process-stored in virtual optical queues ;sent after batch period based on a policy

• Provisioning (wavelength, time slots, signature codes) with traffic awareness

MAC Layer Issues

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Studies on WDMStudies on WDM--Based Access Based Access NetworksNetworks

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WDMOAN with Ring-on-stars Topology

• Larger areas and BW intensive ONUs

• Collection & distribution (C/D) through Star Coupler

• Feeder network : Wavelength-routed WDM ring

• Access node : Router, Scheduler and a Passive Star Coupler• Traffic: Intra cluster (C/D n/w); Inter cluster (Feeder n/w)

CO-

Central office; ONU –

Optical Network Unit ; OLT –

Optical Line Terminal; PSC-Passive Star CouplerC/D Network

Feeder Ring

OLT

CO

Hierarchical Ring-on-a-stars topology

OLT

OLT

OLT

OLT

ONUs

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Salient Features of WDMOAN

• A Backbone ring supporting star-connected user-cluster communication

• Architecture is predominantly “active”

with expensive ONUs

• Fixed Assignment (source-destination pair) wavelength routing of optical channels carrying feeder traffic

• Access Node consists of a Router, Scheduler and a Broadcast Star Coupler

• Scheduler-based MAC protocols in a WDM based Access Network

• Scheduler role in Intra cluster Communication:- Contention–based (Aloha) control trmn. for access requests on control channel - Ranging and Look-ahead features in access grants- Pre-transmission co-ordination based data transmission

• Scheduler role in Inter cluster Communication:-Separate queues for RT and NRT data packets -Priority queuing of traffic (Dynamic BW Management)-O-E-O conversion for mapping intracluster

-

λ

traffic to feeder-λ

traffic

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Proposed Access Node (OLT) Architecture for WDMOAN

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Pre-transmission coordination (PC):

• Aloha protocol for control channel (c

)

• OTs

send reservation requests repeatedly; update requests after random time

• The requests contain the status of the queue

Master/Slave Scheduler-based transmissions:

• Hub issues permits on c

’

after scheduling the requests received on c

• Hub adjusts transmissions of c

’-packets (synchronization and ranging )

• Look-ahead to avoid head-of-line blocking

MAC protocol for Intra-Cluster Traffic

Look-ahead Scheduling

2 3 3*

3 1* 3

1 1 1

Queue 1 (OT 1)

Queue 2 (OT 2)

Queue 3 ( OT 3)

HUB

OT #1

OT #2

OT#N

wc 1,

wc 11 ,

Scheduler Controller

OT Optical terminal1

· · · w : Data channelsc

, c

’

:

Control channel

Ranging

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1

23

4

5

Feeder Ring

Inter-cluster traffic

Intra-cluster traffic

F1

F2

Access Node

•Bandwidth Management Schemes :

-

Non-preemptive priority scheme

-

Preemptive resume priority scheme

• Fixed Wavelength Assignment: Priority-based real-time and non-real-time data

packets multiplexed on same wavelength (for a given destination node)

MAC protocol for Inter-Cluster Traffic

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Bandwidth Management Schemes (DBM)

Real-time packetsNon-real-time packets

3

4

5

6

2

7

Packet generator

1

Real-time queue

7 26

5 34

Non-real-time queue

1

Server

Preemptive Resume Priority

Non-Preemptive Resume Priority

Serving of packet 1(non-real) interrupted and switched over to real-time immediately after packet 2 (real-time) arriving

Serving of packet 1(non-real) completed and then switched over to real-time after packet 2 (real-time) arriving

2

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Delay Analysis for Intercluster

Communication

R T1 1

N R T1 1 2 2

R 1T o tal d elay fo r R T p k ts ., T = +(1 -ρ ) μ

R 1T o tal d elay fo r N R T p k ts ., T = +(1 -ρ )(1 -ρ -ρ ) μ

Non-preemptive resume priority queuing

Preemptive resume priority queuing

1 R T1

R T1

1 2 N R T2

N R T1 1 2

1 (1 ) RT otal delay fo r R T pkts., T =

(1 )1 (1 ) R

T otal delay fo r N R T pkts., T = (1 )(1 )

Delay T is expressed in terms of mean residual time R, waiting time in the queue and average service time 1/μ

for real-time and non-real time data traffic using Little’s

theorem and Pollaczek

Khinchin

formulae

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64

Simulation Results : Intra-cluster Traffic

Nodes=21, Channels=6, 1 : 50 pkt. ratio, k=1

Effect of control ch. count and look ahead

Observations:• More control channels can improve the delay performance until the load per ONU approaches the

take-off point

(load x ONU/ctrl. ch.s=1)

• Delay performance is much more improved with SCM

•With k=1 to 7, the effect of receiver contention is gradually overcome

improving throughput

(saturates when ONU-to-channel ratio becomes 1

)

7 ONUs

and 7 intracluster

wavelengths

System throughput with look-ahead, k

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NCC-2011 Tutorial

65

Numerical Results: Inter-cluster Traffic

Observations:•NRT delay profile is highly sensitive to the RT traffic in both schemes

•Take-off points take place in the vicinity of 2

= 1-

1

•The delay for NRT packets is relatively high in premptive

resume priority (for high RT traffic)

Non-preemptive Priority

Non-real-time traffic(2

)

1

= 0.7 1

= 0.31

= 0.6

1

= 0.2

Pre-emptive Priority

Non-real-time traffic(2

)

1

= 0.71

= 0.6 1

= 0.31

= 0.2

Delay characteristics of non real-time traffic

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66

Numerical Results : Inter-cluster Traffic

Observations:•In non preemptive resume priority scheme, the NRT traffic shows some impact on the RT packet delay

•

In case of preemptive resume priority the delay for RT data packets is independent of arrival of NRT packets

Non-preemptive Priority Pre-emptive Priority

2

= 0.2 to

0.7

Real-time traffic (1

) Real-time traffic (1

)

2

= 0.7 to

0.6

2

= 0.3 to 0.1

Delay characteristics of real time traffic

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67

Numerical Results : Inter-cluster Traffic

Non-real-time arrival 2

= 0.2

Difference in delay for non-real-time traffic -----Difference in delay for real-time traffic

Real-time arrival 1

= 0.2

Difference in delay for non-real-time traffic -----Difference in delay for real-time traffic ___

Non-real-time traffic (2

)

Differential delay

between the two schemes for RT/NRT traffic

Real-time traffic (1

)

Observations:•For a low NRT traffic: The delay difference for NRT data packets

increases with increase in RT traffic, whereas for RT data packets, it decreases more significantly with knee portion around 0.6

•For a low RT traffic:

The delay difference for NRT packets remains constant with varying NRT traffic

whereas for RT data packets, it drops linearly with nominal decrease

Jayashree

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NCC-2011 Tutorial

Conclusions

MAC protocols in a WDM-based optical access network with ring-on-stars topology for incorporating Dynamic Bandwidth Allocation based service differentiation

•

Scheduling improved with more control channels, sub-carrier multiplexing and look ahead feature

• Real time services (voice, video) benefit in preemptive priority queuing at high real-time traffic

• Non real-time service (data, image) quality not affected by preemptive queuing for low real-time traffic

Jayashree

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69Jayashree

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70

System Architecture of AWG-based WDMPONArrayed Waveguide Grating-Based Wavelength Routed Passive Optical Network

r1 , r2 .…. , rNWDM Transmitter

Burst mode WDM Receiver

OLTAWG-Based RN

.

.

RN

Feeder Segment

ONU –

Optical Network Unit OLT –

Optical Line Terminal RN–Remote Node

ONU #1

WDMMUX/

DEMUX

FTt1

ONU #N

FRr1

tN

rN

t1 , t2 .…. , tN

Salient Features:• Architecture is predominantly “passive”

with inexpensive ONUs• Distribution with one or more stages of AWG-based RNs• Wavelength Routing-based Demultiplexing

System Considerations:•Tunable Laser Source in OLT ; Fixed tuned transceiver in ONU

• up -

dn

= n x FSR of AWG ; AWG-based demultiplexer

in RN• OLT-ONU: 20 Km; IM-DD signal transmission

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71

Condition to be met for signal on

from ith

port to appear at kth

port

• Principle:

Light signal after diffraction in i/o slab waveguide is subjected to

dependent progressive

phase delay in slab regions and

w/g

array. After constructive interference

it

is routed to a unique

o/p

port

• AWG is less lossy

with flat pass band and polarization independence

• Easy to realize on integrated optic substrate and amenable to mass fabrication

Arrayed Waveguide Grating Device (AWG)

Input coupler

Output coupler

Input waveguidesOutput waveguides

Arrayed waveguides

1 2 12 1, ..in ou t

ijk ik kjn d n k L n d k m

integeranisp2 xpijk

dikdkj

L

i kj

Enabling Device Technology-

Arrayed Waveguide Grating

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72

Wavelength Routing Mechanism in AWG

Θi

λ

–1 > λ

0 > λ

1

λ

-2 λ

–1 λ

0 λ

1 λ

2

O/p Slab Waveguide

I/p Slab Waveguide

Θo

AWG Device Based Demultiplexer

2

1

0

-1

-2

λ

2

λ

1

λ

0

λ

-1

λ

-2

Far Field Pattern of Routed Optical Channels in a AWG based Remote Node(considering the lorentzian

laser emission Spectrum , dispersion and Gaussian focal field)

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73

Factors affecting the optical channel

•Laser related:

Laser linewidth, Laser transmit powerFinite Laser Line-width

due : Lorentzian

Emission Spectrum -

Spillover to adj. ch-

Produces hetero wavelength crosstalk at o/p

ports

• AWG related:

Far-field image profile, Heterowavelength

crosstalk and DispersionGaussian Far-field Pattern: Effect of dispersion in Slab waveguides

-

Results in non-uniform routed signal power at o/p

Ports

• Photo detector related :

Beat noise (between signal and cross talk)Beat Noise: By-product of constructive interference phenomenon in AWG

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74

Far Field Distribution at the Image Plane of AWG (due to dispersion):

Performance Analysis –

AWG Model

2

22

thOptical Power at the i output port, ( )i

wio oP P e

Lorentzian

Power Spectral Density of the Laser at center frequency foi

:

2

2 22

L

1 1( )4

1 1

where B laser line width ; Laser freq. noise spectral density )2

iO oi oi

o o

LO

AS fN f f f f

N N

dB

Transformation from Spectral Domain to Radial (Angular) Domain:

DθR

iDθR

fiffff

DθR

ffffRDθ

chaachooi

aoo

a

)()(

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NCC-2011 Tutorial

75

Performance Analysis -

AWG Model:

Considering only the real frequencies in the PSD of the laser emission spectrum, thetransformed Lorentzian

power spectral density of the laser, operating at foi

)()(222

1

12

in

io

DLBchaR

iDLBaR

Li SP

BAS

DBR

eADB

ReAP

L

wgai

L

wgai

isig

w

ch

w

ch

1)(22

1)(22

tantan22

2

2

2

2

On integration, total optical signal power captured at the ith

port is given by:

On integration, total inter-channel (hetero-wavelength) crosstalk at the ith

port is given by::

2

21tan2

21tan2

2)1(2

2

2

2

21tan2

21tan2

2)1(2

2

2

wgchDLB

aRwgchDLB

aRw

chi

eA

wgchDLB

aRwgchDLB

aRw

chi

eAi

xtP

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76

Transmission Impairments:Direct Noise Components


BER Evaluation

2)(n pBnPR2qσ channels,adjacent n from Variance talk Cross

BP2qRσ bit, “1”for Variance NoiseShot

BP2qεqσ bit, “0”for Variance NoiseShot

R4KTB

Bησ Variance, Noise Thermal

R4KTB

Bησ Variance, Noise Thermal

adjonreadjixtλ

2xt

eisigλ

2sh1

eisigλ

2sh0

L

eeth

2th

L

eeth

2th

Beat Noise Components

)1(2 Variance,Beat talk Cross- talkCross

2 Variance,Beat talk Cross-Signal

211

22_

22_

adjonri

adji

adjpolxtxt

onri

xti

sigpolxtsg

npPPR

pPPR

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NCC-2011 Tutorial

77

Various Noise factors and their standard deviations :


BER Evaluation

' 2 2 20 0 xt

' 2 2 21 sh1 xt

Without Beat Noise:

Total Noise Standard deviation for “0” bit,

Total Noise Standard deviation for “1” bit, With Beat Noise:

Total Noise Standard deviation for “0

th sh

th

2 2 2 20 0 xt _

2 2 2 2 20 1 _ _

” bit,

Total Noise Standard deviation for “1” bit,

Optimized Decision Threshold:

Detection threshold independent of beat noise (practical),

th sh xt xt

th sh xt xt xt sig xt

I

' '0 1

1 ' '1 0

1 1

1 0

Probability of Bit Error Rate:

14 2 2

sig sigth

sig sigth the

R P R P

R P I I R PP erfc erfc

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78

• Optical Channels (= port count) : 16; OLT Transmit power levels–

Class B PONsLaser Linewidths: 100 MHz-5 GHz range; Wavelength channel spacing: 100/50/25 GHzData rates: 155/622 Mbps; Insertion loss of AWG is 6.5 dB; fiber

span of 20 Km @0.25dB/Km

• Thermal noise dominates the link budget of the wavelength channels in a WDMPON because of cost-effective photo-receivers (6pF capacitors)

• Full FSR has not been used. The output port-aperture is only a fraction of a FSR or the main focal spot

• Receiver waveguide width is typically that of a SM fiber

System Considerations

Jayashree

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NCC-2011 Tutorial

79

Numerical ResultsSignal loss and Crosstalk variation at output ports

Jayashree

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NCC-2011 Tutorial

Loss Characteristics of AWG for different laser linewidths; Rb

= 1.25Gbps; POLT = -6.0 dBm; AWG Insertion loss = 6.5 dBInter-channel Crosstalk Characteristics for 1.25Gbps channels; POLT = -6.0dBm

80

Numerical ResultsBER variation at output ports

Jayashree

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NCC-2011 Tutorial

BER characteristics of 1.25 Gbps

channels for different laser linewidths

without including beat noise: POLT=−6.0 dBm, ch

=100 GHz.

81

Numerical Results

Jayashree

Ratnam


NCC-

2011 Tutorial

BER Characteristics of 10.0Gbps channels for different laser linewidths; POLT = +3.0 dBm; Δch

=100GHz

1e-011

1e-010

1e-009

1e-008

1e-007

1e-006

1e-005

0.0001

0.001

0.01

0.1

-8 -6 -4 -2 0 2 4 6 8

BER

Output Port of the Remote Node

OLT Power = -6.0dBm, Laser linewidth = 500.0MHzLaser linewidth = 1.5GHzLaser linewidth = 3.0GHz

OLT Power = 3.0dBm, Laser linewidth = 500MHzLaser linewidth = 1.5GHzLaser linewidth = 3.0GHz

Impact of OLT Transmit Power on BER variation at output ports

82

Numerical Results

Jayashree

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NCC-2011 Tutorial

Comparative Crosstalk Characteristics for different data rates and port locations

BER versus laser linewidth

for different data rates at Port #0; BL = 500 MHz;

83

Numerical Results

Jayashree

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NCC-2011 Tutorial

BER performance of 1.25 Gbps

channels including beat noise for different port counts: POLT=−6.0 dBm, BL=500 MHz, ch=100 GHz.

Conclusions

Impact of transmission impairments in an AWG-based PON

•Gaussian focal-field pattern of the AWG largely determines the signal strength of the demultiplexed

channels at the output ports

•Beat noise effects become more conspicuous in PONs, for increasing values of laser linewidth

especially at the inner ports

•Impairments bring a significant BER variation amongst the ONUs

connected to the output ports of a AWG while employing DFB lasers at the OLT.

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86

Scalability and resource provisioning-

Modular scaling (in terms of clusters)-

Increased resource pool (codes/time slots/RF sub-carriers etc.,)

Effective bandwidth utilization per wavelength-

Finer granularity in provisioning within a λ

Reduced ONU cost due to more sharing and less inventory -

Fewer port counts and transceiver with shorter tuning range -

WDM transceiver common for all ONUs

within a code-cluster

Derive combined strength of constituent access and MUX schemes-

Compensate limitations

of independent schemes

Better network resilience -

ONU less prone to failure (semi-passive)-

Restoration cheaper (low inventory cost)

Impetus for a Hybrid WDMPON

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NCC-2011 Tutorial

OLT – Optical Line Terminal

RN–Remote Node

ONU – Optical Network Unit

OLT RN

Schematic of a Hybrid PON

RN

ONU

ONUONU

RN

ONU

ONUONU1st

Stage

2nd

Stage

87

•Passive Architecture: Fiber Bragg Grating-based CODECs, Arrayed Waveguide Grating-based Mux/Demux, Circulator, Passive Star Coupler

•Asynchronous access: Free of time synchronization between ONU’s

and OLTIdeal for bursty

data traffic

• Hybrid multiplexing and multiple access (WDM/OCDM techniques)

•Resource Optimization: Reduced no. of wavelengths (λ/cluster)Reuse of a set of optical codes in several clustersNo separate laser in

the ONU (downstream laser power reusedthrough Reflective Semiconductor Optical Amplifier-RSOA)

•Scalability: Upstream codes reduced and downstream users increased

•Operating conditions: W-OCDM PON using (341,5,1) OOC with 17 codes; Asymmetric traffic with up:down

ratio 0.25 to 0.9; PON span: 20-25Km; ONUs: 255 (=15 x 17)

Salient Features of a WDM-OCDMA PON

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88

System Architecture of WDM-OCDMA PON

Received downlink signal

Baseband

uplink signal

ONU Transceiver

PSC

COUP

RSOA

PDFBG Coder

FBG Decoder

Passive Star Coupler

Remote Node

Fiber Bragg Grating-based ONU Transceiver

.

.

OLT RN

RN

RN

.

.

.

1st

Stage RN

2nd

Stage RN

.

.

λ1

……. λ12λ1

. .

λ4

λ9

. .

λ12

λ1

λ4

OCDMA CLUSTER #12

λ9

λ5

. .

λ8

.

.FBG

RSOATXCVR

FBGRSOA

TXCVR

ONU #1

ONU #N

OCDMA CLUSTER #1ooc1

oocN

System Architecture of a Scalable WDM-OCDMA PON

CLTR

ONU –

Optical Network Unit OLT –

Optical Line Terminal RN–Remote NodePSC-Passive Star Coupler (splitter/combiner)CLTR –

CirculatorFBG –

Fiber Bragg Grating (Codec)RSOA-

Reflective Semiconductor Optical Amplifier

PSC

.

.

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NCC-2011 Tutorial

89

Hybrid Transmission Mechanisms

: -WDM/OCDM multiplexing downstream-WDMA/OCDMA multiple access upstream-

N x M

ONUs

with

unique wavelength-code combination

Passive Architecture

: Two stage distribution-

PSC-based RN handles OOC-encoded ONU traffic-

AWG-based

RN handles aggregated WDM traffic -

Fiber Bragg grating-based CODECs

for ONUs

Asynchronous access: -

Free from time synchronization between ONUs

and OLT-

Ideal for bursty

data traffic

Resource Optimization: -

Reduced no. of wavelengths i.e., simpler OLT-

Reuse of optical codes in several clusters-

No separate laser in the ONU (RSOA)

Provisioning:

-

Each ONU-cluster allocated a wavelength-

Every ONU allotted distinct code for downstream transmission-

Shared codes for upstream transmission (code contention)-

Traffic asymmetry accounted

Data Security: Inherent coding mechanism enhances confidentiality in n/w

Salient Features of W-OCDM PON

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90

Optical Orthogonal Codes (OOCs)-

Unipolar

coding for IM data streams-

Selection criteria: cluster size and data rate per user

Proposed Code Allocation Scheme-

Heuristic estimate based on traffic ratio β-

Open search mode using deviation Δ

for optimal solution

Major Impairments affecting the Performance-

Multiple user interference (MUI) and code contention

Performance Criteria-

Aggregate throughput in upstream and downstream directions

Operating conditions:-

OOC (364,4,1) i.e., cluster size M=30 -

Slotted ALOHA protocol-

ONUs

operate in duplex mode -

Fiber link : 2.5 Gbps

with 6.6 Mbps/channel -

Data packet size Plen

:150/ 75 /20 bytes-

Binomial distributed

traffic with β

=0.25/ 0.5/0.75/0.9-

PON span: 20-25Km ; Total ONUs: 30xN (N=λs)

Resource Provisioning through a Code Allocation Scheme

Code Family Code Charact.C=(n,w,λ)

Code Size|C|=[(n-1)/w(w-1)]

(n,3,1) (31,3,1) 5

(63,3,1) 10

(127,3,1) 21

(255,3,1) 42

(511,3,1) 85

(1023,3,1) 170

(2047,3,1) 341

(4095,3,1) 682

(n,4,1) (40,4,1) 3

(121,4,1) 10

(364,4,1) 30

(1093,4,1) 91

(3280,4,1) 273

(n,5,1) (85,5,1) 4

(341,5,1) 17

(1365,5,1) 68

(5461,5,1) 273

Table 1. Some OOCs

and their Characteristics

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91

Resource Provisioning through a Code Allocation Scheme

Time slot, t

Heuristic Code Allocation:

1 ; ~ ( 1)

; ( - ) (1 )

upd

dn

up d dn d up

GnCw w G

N C N C N

Gup

/Nup

= Pkt. traffic /Codes in upstream direction

Gdn

/Ndn

= Pkt. traffic/Codes in downstream direction

β= 0.5 or 1:2

Cup-3

β= 0.25 or 1:4

Cdn-1

Cup-3

β= 0.75 or 3:4

Cdn-2

Cdn-3

Cdn-4

Cup-3

Cup-1

Cup-2

Cup-2Opt

ical

Tra

nsm

issi

on

Cha

nnel

Cdn-1

Cdn-2

Cdn-3

Cdn-4

Cdn-1

Cdn-2

Cdn-3

Cdn-4

Cdn-1

Cup-4

β= 0.9 or 9:10

Cdn-2

Cdn-3

Cdn-4

Cup-3

Cup-2

Cup-1

MUI only MUI &CNT MUI &CNT MUI only

DN

UP

Packet Transmission under different traffic conditions

DN

UP

Towards OLT

Towards ONU

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92

Performance Analysis of W-OCDM PON

m ax m ax

11

( )=

( )=

( )

no . o f packet transm issionspacket arrival p robab ility p robab ility o f d istinct code usage

p rob

( ) . ( ) . ( ) . ( ) (1)

ab il

k

N

d

N

c

cdk

w heref

P

P

k kS S k k f k P k P k

kkk

k

m ax ity o f co rrect packet transm ission under M U I

m axim um no. o f transm issions in a d irectionk

( ) . . 1 (Binomial) ( 2)k N kup

up up upupN

up dn dn

up up

up

Nf

k N N

N Nk

Packet arrival probability (upstream)

:

. ( )

( ) (3)

up up

upd up

up

N kgmk

N dnk

P k

Distinct code usage probability:

System Throughput in a Code-cluster

Correct packet transmission probability under MUI:int

2 2. ( ). 1 (4)( ) 1

i k ik intintkup NC len dndn i w

Pk w w

fi n n

P k

max

max

Upstream channels: &Downstream channels: &

up up

dn dn

k k k Nk k k N

int

m

len

no. of interferers g no. of contenders for a upstream code

data packet length in bytesP

k

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NCC-2011 Tutorial

93

Upstream throughput in an ONU-cluster:

11

With Code Contention:

up

Nup Nupup kupk

k N kup up upup up

dn dn

N

upbinom a

N N

i l

Nk

S

2 2( )

1 ( ) 1

dn

up i k ik intintint

len N dni w

upup

dnup

kN gmk

Nk

Pk w wf Ni n n

1

upWith Contention Avoidance:

(5a )

SNup

upup

k upup

binomial

N

kk

2 2

1 1 ( ) 1

dn

i k ik N k k intup up up intup up int

len N dni wdn dn

N NP

N N

k w wf Ni n n

) 1

where,

(

(5 b )

kdndn dn dn

N dndndn dn

N

k N

N Nf N

intand ( 1 ) N kdn dn

up dndnN

k k N


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NCC-2011 Tutorial

94

Downstream throughput in an ONU-cluster:

2 2int

1

1

where,

(

)

6)

(

1 ( ) i k ii

k N kup up

nt

upup upN up

dnbi

int

up

dn len Nnomia

d

upupi

n dn

wl

upup

k

N N

N N

w w

n n

Nk

P

f k

kN f k

iS

intand ( 1 ) dn upkk k

Important regions in performance curves: Cut-off point vis-a-vis

heuristic estimate-

extent of deviation from traffic-aware allocation

Over-provisioned region (cut-off point at +ve

Δ)-

trade-off between per-user rate and reduced cluster size

• Under-provisioned region (cut-off point at -ve

Δ)-

scope for spare codes / scalability


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NCC-2011 Tutorial

95

Throughput Analysis of W-OCDM PON

m ax m ax

1 1

( ) S teady-S tate d istribu tion P robability o f

N o . o f upstream transm issions

u

U pstream throughput, ( ) . ( ) . ( ) . ( )

=

up

up up

up

up up up N up d up c upk k

up

N up up

w here

f

k kS S k k f k P k P k

k

k k

packets

( ) = P robab ility o f k d istinct codes sub ject to code con ten tion

( ) P robab ility o f correct txm n. o f packets sub ject to m ultip le user in terference

p stream

d up

c up

P

P

k

k

m ax upk N

Upstream Traffic:

Downstream Traffic:

m ax

1 1

w here

S teady-S tate d istribu tion P robab ility o f

N o . o f dow nstream transm issions

dow

D ow nstream throughput, ( ) . ( ) . ( ) . ( )

= ( )

dn

dn dn

dn

dn

dn dn dn N dn d dn c dnk k

dn

N dn dn

k NS S k k f k P k P k

kf k k

m ax

packets

( ) = D istinct C ode P robability sub ject to code con ten tion =1

( ) C orrect P acket P robab ility sub ject to m ultip le user in terference

nstream

d dn

c dn

dn

P

P

kk

k N

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NCC-2011 Tutorial

96

Throughput Analysis of W-OCDM PON

. ( ) . ( )( )

( )( )

where ( ) is the total combinations & P ( ) is the distinct combinations

up

d

up up

up up

up up

up up

upup

up

Ng k kg gm mk k

N Ndn dnk k

P kP

Q k

Q k k

k

( ) . . 1 (Binomial distribution)up up up

up

k kup

up dn dn

Nup up

N up

Nf

k N N

N Nk

Code Contention:

Packet arrival probability:

Correct packet probability under MUI:

len

2 2

. ( ). 1

Probability of correct packet transmission for a data packet length of P is given by

( ) 1 cnt

intint

C up len dni w

dn

i k ik

N

k w wP f k

i n nP k

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NCC-2011 Tutorial

97

Numerical ResultsUpstream data rate throughput (2.4 Gbps symmetric)

Jayashree

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NCC-2011 Tutorial

0

10

20

30

40

50

-4 -2 0 2 4 6 8 10

Ups

tream

Agg

rega

te T

hrou

ghpu

t, M

bps

Deviation from Heuristic Upstream Code Esimate

Upstream:Downstream Code Breakup at zero deviationTraffic ratio=0.25;codes-6:24Traffic ratio-0.5;codes-10:20

Traffic Ratio=0.75;codes-12:18Traffic ratio-0.9;codes-14:16

0

10

20

30

40

50

-4 -2 0 2 4 6 8 10

Ups

tream

Thr

ough

put i

n M

bps

Deviation from Heuristic Upstream Code Estimate



Effect of packet length on upstream throughput with code contention; OOC = (364,4,1); Users = 30; Packet size = 150B

Upstream throughput versus ∆

with code contention; OOC = (364,4,1); Users = 30; Packet Size = 75B

98

Numerical Results

Upstream data rate throughput (2.4 Gbps symmetric)

Jayashree

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NCC-2011 Tutorial

0

10

20

30

40

50

-4 -2 0 2 4 6 8 10

Ups

tream

Agg

rega

te T

hrou

ghpu

t in

Mbp

s


Upstream:Downstream Codes Breakup at zero deviationTraffic ratio=0.25;codes-6:24;Pkt.size=75B

Pkt.size=20BTraffic Ratio=0.5;codes-10:20;Pkt.size=75B

Pkt.size=20B

Effect of packet length at low to medium β

on upstream throughput with contention avoidance; OOC = (364,4,1); Users = 30

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Uptream:Downstream Code Break-up at zero deviationTraffic ratio=0.25;codes-6:24Traffic ratio-0.5;codes-10:20


Downstream aggregate throughput versus ∆; OOC = (364,4,1); Users = 30; Packet size = 75B

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Upstream throughput versus ∆; OOC = (341,5,1); Users = 17; Packet size = 1500B

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Effect of packet length on upstream throughput with code contention; OOC = (364,4,1); Users = 30; Packet size = 150B

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User-

total throughput product Q

versus ∆; OOC = (341,5,1); 17 users; Packet size = 1500B

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IEEE ANTS 2008 Jayashree Ratnam 101

ConclusionsResource provisioning aspects of a W-OCDM PON using Heuristic optical code allocation approach

• Hybrid WDM PONs

offer resource provisioning with finer granularity in bandwidth

utilization

•Bidirectional traffic performance in a code-cluster is affected both by MUI and code contention, depending upon the traffic ratio in a PON

• Medium to high β

PONs

are capable of network expansion through the use of contention avoidance schemes

• For a given OOC, a trade-off exists between data packet length and user-cluster size due to MUI constraint

• Low β

PONs

benefit from over-provisioning by improving per-ONU data rate

•

Medium to high β

(>0.5) PONs

support n/w

scaling under a contention avoidance scheme provided packets are short

•

OOCs

with high n/w

ratio are crucial for MUI-constrained PONs

albeit with a trade-off between system throughput and per-ONU data rate

102

Final Remarks

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NCC-2011 Tutorial

•FTTP technology created an unchallenged niche in telecom access segment throughpassive, point-to-multipoint PON technology

• WDM in combination with TDM and OCDM can be significantly improve the scalability and provisioning aspects of PONs

• NexGen

PONs

are expected to deliver: new and legacy services, both analog and digital in a single converged conduit

• NGPONs

should gear up for serving as mobile backhaul networks with high accuracy of the clock timing for mobile services

• Burst-mode transceivers, Colorless ONUs

hold the key to massive deployment of NGPONs

•Scheduling policies accounting for traffic and multi-service characterization can deliver bandwidth efficient and fair bidirectional transmissions

• A synergy between fiber –based PONs

and advanced wireless technologies alone assuresfuture-proof access network infrastructure

• FTTP being a

“GREEN“

technology

(low energy with lifetime emissions reduced by 50% ) is bound to receive attractive incentives from many nations world over

103

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Division –Multiplexed Passive Optical Network (WDM-PON) Technologies for Broadband Access: a Review”, Journal of Optical Networking, vol. 4, no.11, pp. 737–758, Nov. 2005.

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Technology, vol. 16, no. 9, pp. 1546-1559, Sept. 1998.

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Technology, vol. 25, no. 11, pp. 3428-3442, Nov. 2007.

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[KrMP01] “G.Kramer, B. Mukherjee

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and Analysis of an Optical Access Network,”

Photonic Network Communications, vol.3, no.3,pp.307-319, July 2001.

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and I. P. Kaminow, “LARNET, a local access router network,”

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[EfBa09] Frank Effenberger, Tarek S. El-Bawab, “Passive Optical Networks (PONs): Past, Present and Future”, Journal of Optical Switching and Networking, Elsevier, 6(2009) 143-150.

[JOCN09] Special issue, PONs: “Technologies, Architectures, and Deployment Strategies”,

Journal of Optical Switching and Networking, Elsevier, 6(2009) 143-150.

[EfKM10] Frank J. Effenberger, Jun-ichi

Kani, and Yoichi Maeda, “Standardization Trends and Prospective Views on the Next Generation of Broadband Optical Access Systems”, IEEE Journal of Selected Areas in Communications, vol. 28,no.6, August 2010

[GuGD09] A. Gumaste, P. Gokhale

and A. Dhar, “On the State and Guiding Principles of Broadband in India”, IEEE Communications Magazine, Vol.47, No. 8, Aug. 2009

[KBCR09] J.Kani, F. Bourgart

et.al, “Next Generation PON-Part I: Technology Roadmap and General Requirements”, IEEE Communications Magazine, Vol.47, No. 11, Nov. 2009

[EMPP09] Frank J. Effenberger, Hiroaki Mukai, Soojin

Park, Thomas Pfeiffer, “Next Generation PON-Part II: Candidate Systems forNext-Generation PON”, IEEE Communications Magazine, Vol.47, No. 11, Nov. 2009

[EMKR09] Frank J. Effenberger, Hiroaki Mukai, Jun-ichi

Kani, Michael Rasztovits, “Next Generation PON-Part II: System

Speceficationsfor

XGPON”, IEEE Communications Magazine, Vol.47, No. 11, Nov. 2009

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[MoBa00] E. Modiano

and R. Barry, “A Novel Medium Access Control Protocol for WDM-Based LAN’s and Access Networks using a Master/Slave Scheduler, IEEE/OSA Journal of Lightwave

Technology, vol. 18, no. 4, pp. 461-468, Apr. 2000.

[KGTK05] K. S. Kim, D. Gutierrez, F. Tai and L. G. Kazovsky, “Design and performance analysis of scheduling algorithms for WDMPON under SUCCESS-HPON architecture,”

IEEE/OSA Journal of Lightwave

Technology, vol. 23, no. 11, pp. 3716-3731, Nov. 2005.

[RSVD07] J. Ratnam, R. Shyamsukha, S. Vuta, A. Joglekar, G. Das

and D. Datta, “Medium Access Control Protocols for WDM-based Optical Access Networks with Passive-Star Clusters Interconnected by a Backbone Ring”

Computer Communications, Elsevier, vol. 30, Issue 18, pp. 3614 -3626, Dec. 2007

[KrMP05]G. Kramer, B. Mukherjee, Gerry Pesavento, “Interleaved Polling with Adaptive Cycle Time (IPACT):A Dynamic Bandwidth Distribution Scheme in an Optical Access Network, OSA Journal of Optical Networks, vol. 4, no. 11, pp. 737-757, Nov. 2005

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vol. 29. no. 6, pp. 895–901, Jun. 1981.

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and C. A. Brackett, “Code Division Multiple Access Techniques in Optical Fiber Networks-Part II: Systems Performance Analysis,”

IEEE Transactions on Communications, vol. 37, no. 8, pp. 834–842, Aug. 1989.

[Ratn02]J. Ratnam, “Optical CDMA in Broadband Communication -

Scope and Applications,”

Journal of Optical Communications,

Fachverlag

Schiele

& Schön,

vol. 23 (2002) 1, pp. 11-21

[BeGa97] D. Bertsekas

and R. Gallager, Data Networks, Prentice Hall Inc., USA, Second Ed., 1997.

[RaCD09] J. Ratnam, S. Chakrabarti

and D. Datta, “A Heuristic Approach for Designing Hybrid PONs

Employing WDM and OCDMA with Asymmetric Traffic Distribution,”

Optical Switching and Networking, Elsevier, vol. 6, Issue 4, pp. 235 -242, Dec. 2009

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[RDFH99] B. Ramamurthy, D. Datta, H. Feng, J. P. Heritage and B. Mukherjee, “Impact of Transmission Impairments on the Teletraffic

Performance of Wavelength-Routed Optical Networks”, IEEE/OSA


Technology, 17(10): 1713-1723, Oct. 1999.

[Salz86] J. Salz, “Modulation and Detection for Coherent Communication”, IEEE Communications Magazine, pp. 38-49, June 1986.

[SmDa96] M. K. Smit

and C. V. Dam, “PHASAR-Based WDM-Devices: Principles, Design and Applications”, IEEE Journal of Selected Topics in Quantum Electronics, 2(2): 237-250, June 1996.

[TOTI’95] H. Takahashi, K. Oda, H. Toba

and Y. Inoue, “Transmission Characteristics of Arrayed Waveguide N x N Wavelength Multiplexer”, IEEE/OSA


Technology, 13(3): 447-445, Mar. 1995.

[TaOT96] H. Takahashi, K. Oda

and H. Toba, “Impact of Crosstalk in an Arrayed-Waveguide Multiplexer on N x N Optical Interconnection”, Journal of Lightwave

Technology

14 (6): 1097-1105, June 1996.

[HLXL07] W. P. Huang, X. Li, C-Q. Xu, X. Hong, C. Xu

and W. Liang, “Optical Transceivers for Fiber-to-the-Premises

Applications: System Requirements and Enabling Technologies”, IEEE/OSA


Technology, vol.25, no.1, Jan. 2007.

[RaCD10] J. Ratnam, S. Chakrabarti

and D. Datta, “Impact of Transmission Impairments on Performance of WDMPONsEmploying AWG-based Remote Nodes”, IEEE/OSA Journal of Optical Communication and Networking,

vol. 2, Issue 10, pp. 848-858, Oct. 2010

[WoLA07]E. Wong, K. L. Lee and T. B. Anderson, “Directly modulated self-seeding reflective semiconductor optical amplifiers as colorless transmitters in wavelength division multiplexed passive optical network,”

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Technology, vol. 15, no. 1, pp. 67-74, Jan.2007.

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107Jayashree

Ratnam


NCC-2011 Tutorial

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